ASoC: BCM2708: Add 24 bit support

This adds 24 bit support to the I2S driver of the BCM2708.
Besides enabling the 24 bit flags, it includes two bug fixes:

MMAP is not supported. Claiming this leads to strange issues
when the format of driver and file do not match.

The datasheet states that the width extension bit should be set
for widths greater than 24, but greater or equal would be correct.
This follows from the definition of the width field.

Signed-off-by: Florian Meier <[email protected]>

Author: koalo

sound/soc/bcm/bcm2708-i2s.c

@@ -346,6 +346,10 @@ static int bcm2708_i2s_hw_params(struct snd_pcm_substream *substream,
 		data_length = 16;
 		bclk_ratio = 40;
 		break;
+	case SNDRV_PCM_FORMAT_S24_LE:
+		data_length = 24;
+		bclk_ratio = 40;
+		break;
 	case SNDRV_PCM_FORMAT_S32_LE:
 		data_length = 32;
 		bclk_ratio = 80;
@@ -424,7 +428,7 @@ static int bcm2708_i2s_hw_params(struct snd_pcm_substream *substream,
 	/* Setup the frame format */
 	format = BCM2708_I2S_CHEN;
 
-	if (data_length > 24)
+	if (data_length >= 24)
 		format |= BCM2708_I2S_CHWEX;
 
 	format |= BCM2708_I2S_CHWID((data_length-8)&0xf);
@@ -714,13 +718,15 @@ static struct snd_soc_dai_driver bcm2708_i2s_dai = {
 		.channels_max = 2,
 		.rates =	SNDRV_PCM_RATE_8000_192000,
 		.formats =	SNDRV_PCM_FMTBIT_S16_LE
+				| SNDRV_PCM_FMTBIT_S24_LE
 				| SNDRV_PCM_FMTBIT_S32_LE
 		},
 	.capture = {
 		.channels_min = 2,
 		.channels_max = 2,
 		.rates =	SNDRV_PCM_RATE_8000_192000,
 		.formats =	SNDRV_PCM_FMTBIT_S16_LE
+				| SNDRV_PCM_FMTBIT_S24_LE
 				| SNDRV_PCM_FMTBIT_S32_LE
 		},
 	.ops = &bcm2708_i2s_dai_ops,
@@ -810,11 +816,10 @@ static void bcm2708_i2s_setup_gpio(void)
 }
 
 static const struct snd_pcm_hardware bcm2708_pcm_hardware = {
-	.info			= SNDRV_PCM_INFO_MMAP |
-				  SNDRV_PCM_INFO_MMAP_VALID |
-				  SNDRV_PCM_INFO_INTERLEAVED |
+	.info			= SNDRV_PCM_INFO_INTERLEAVED |
 				  SNDRV_PCM_INFO_JOINT_DUPLEX,
 	.formats		= SNDRV_PCM_FMTBIT_S16_LE |
+				  SNDRV_PCM_FMTBIT_S24_LE |
 				  SNDRV_PCM_FMTBIT_S32_LE,
 	.period_bytes_min	= 32,
 	.period_bytes_max	= 64 * PAGE_SIZE,